1. Field of the Invention
This invention relates generally to a check-out device that performs registration of articles to be purchased according to article codes recorded in a mechanically readable form on the articles, and more particularly to a check-out device in which a customer participates a process of entering the article codes.
2. Description of the Related Art
A check-out device is installed, for example, as a self-service check-out counter at a supermarket. A customer puts articles he or she wishes to purchase in a shopping cart, pushes the cart to an input section of the check-out device, and depresses a start button on an operator panel of the input section to register the articles. Then, the customer takes out an article from the cart, sets it in front of a scanner (i.e., an article-code reader) for entering an article code by scanning, and then puts iron the entry conveyor arranged on an electronic weighing device. The scanner optically scans the article to read the article code recorded on the article generally in a bar-code form, and supplies the read article code to an electronic cash register. The electronic weighing device measures the weight of the article on the entry conveyor and supplies a result of the measurement as measured weight data to the electronic cash register. The electronic cash register has an article data table containing article data of all the articles for sales, each data item being composed of, for example, an article code, an article name, a unit price, and a reference weight. The electronic cash register uses the read article code, the measured weight data, and the article data table in order to confirm that an article whose article code is read by the scanner is on the entry conveyor, and the read article code in order to register the article as a purchased article after the confirmation. On the other hand, the article is fed from the entry conveyor to an outfeed conveyor after the confirmation, and further fed to a bagging area by the outfeed conveyor.
After scanning of all the articles to be purchased, the customer depresses a stop button on the operator panel to finish registration of the articles. At this time, the electronic cash register performs settlement for the registered articles based on the article data stored in the article data table. The cashier informs the customer of the total amount of the registered articles obtained in the settlement and stores cash paid by the customer in a drawer of the electronic cash register. After the payment, the customer puts the articles stocked on the bagging area into a bag and leaves the counter.
The above conforming operation is performed each time the electronic weighing device has completed the measurement of the article weight. In this operation, the electronic cash register receives the measured weight data from the electronic weighing device and the read article code from the scanner, and checks to see if the read article code is correct. When the article code is detected to be correct, the measured weight data is compared with the reference weight data of an article identified by the article code. When it is detected that the measured weight data coincides with the reference weight data, the article is registered as a purchased article, using the read article code. This article registration is not carried out if difference is detected. Instead, the entry and the outfeed conveyors are stopped, and then, a message requesting to put the article whose article code has been read on the entry conveyor.
In the aforementioned check-out device, a customer takes a task of inputting article codes with the scanner, whereas a cashier takes a task of operating the cash register to process the input article codes. This shortens the time during which the customer is kept waiting without anything to do, as compared with a case where the cashier takes a task of not only inputting the article codes but also operating the cash register. The load on the cashier is reduced as a result of the customer's cooperation. Use of a scanner eliminates article code input errors that would take place in operating keys to input the article codes. Therefore, this greatly helps customers waiting at the counter to avoid forming a long queue. Further, since the comparison of the weight data items is performed to check to see if an article whose article code has been read is the same as that on the entry conveyor is checked, a dishonest practice by the customer could be prevented. Published Unexamined Japanese Patent Application No. 61-46591 discloses a check-out device similar to that as described above.
Conventional check-out devices have the drawbacks that prevent smooth, quick check-out.
Specifically, the scanner is generally kept in an operable state during the period from when the start button has been depressed to read the article codes from the articles sequentially set in front of the scanner until the stop button is depressed. If the customer skillfully sets the articles one after another in front of the scanner and puts them on the entry conveyor, a subsequent article can be put on the entry conveyor before the electronic weighing device has finished weighing the article now on the entry conveyor. Should this happen, the electronic weighing device produces incorrectly measured weight data indicating the sum of the weight of an article and a subsequent article. Accordingly, due to a difference between the measured weight data and the reference weight data, the article cannot be registered even though it is put on the entry conveyor after the article code thereof has been read.
Further, as for meter-rate priced articles, such as meat, sold at a price of the unit price multiplied by the weight, it is impossible to preset in the article data table the reference weight data covering all variations of article weight. To prevent the aforementioned dishonest practice in registering articles, the cashier must input the article codes of meter-rate priced articles instead of the customer. This, however, reduces the efficiency of the article registration and settlement job.
Even if the weight of a meter-rate priced article is determined, and the reference weight data indicating the determined weight is preset in the article data table, the reference weight data does not always coincides with the measured weight data. For instance, meat or slices of fish are placed on a styrene foam tray of a reasonable size, and wrapped with a transparent film. Small rice crackers are put in a plastic bag. That is, the total weight of the meter-rate priced article varies with the weight of a packaging material added to the net weight of the article. Accordingly, there is a possibility that a meter-rate priced article cannot be registered due to a difference between the measured weight data and the reference weight data.